1. Field of the Invention
This invention relates generally to an optical device employing an optical thresholder and, more particularly, to an optical comparator that employs an optical thresholding device positioned in a propagation path of an optical input beam that provides an indicator signal indicative of whether the intensity of the input beam is above a threshold.
2. Discussion of the Related Art
Advances in signal processing technology, including the need for greater processing speeds, increased channel bandwidths and improved transmission reliability, has resulted in a steadily growing focus on the optical domain and the vast potential that lies therein with respect to these parameters. However, optical technology, as compared to electrical and radio frequency based technology, lacks the necessary technical sophistication in many areas. Particularly, the desire for high-speed, large-bandwidth processing devices employing digital optics has been hampered by the lack of many basic optical devices and technologies readily available in the RF domain.
Optical comparators comprise an example of such a device that has not heretofore met basic design requirements. Similarly, variable optical signal attenuator is another example of a device that has not heretofore met basic attenuator design requirements. An optical comparator that compares an optical signal with an optical threshold and indicates whether the threshold has been exceeded and/or an optical signal attenuator that decreases the intensity of an optical signal by a predetermined amount with little or no reliance on RF technology would reduce system complexity and provide for high speed and large bandwidth processing advances.
What is needed is an efficient, cost effective and reliable optical comparator and variable optical signal attenuator that has application to be used in an optical signal processing system. It is therefore an object of the present invention to provide such an optical comparator and an optical signal attenuator.